Free Vibrations Types Quiz
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Questions and Answers

In which type of vibration do the particles of the shaft or disc move parallel to the axis of the shaft?

  • Lateral vibrations
  • Torsional vibrations
  • Longitudinal vibrations (correct)
  • Transverse vibrations

    • What type of vibrations occur when the particles of the shaft or disc move in a circle about the axis of the shaft?

  • Radial vibrations
  • Torsional vibrations (correct)
  • Longitudinal vibrations
  • Transverse vibrations

    • When the particles of the shaft or disc move approximately perpendicular to the axis of the shaft, what type of vibrations are induced?

  • Torsional vibrations
  • Angular vibrations
  • Transverse vibrations (correct)
  • Longitudinal vibrations

    • Which type of vibration causes the shaft to be twisted and untwisted alternately?

    <p>Torsional vibrations</p> Signup and view all the answers

    If a system executes longitudinal vibrations, what is happening to the shaft?

    <p>It is elongated and shortened alternately</p> Signup and view all the answers

    What type of stresses are induced in the shaft during transverse vibrations?

    <p>Bending stresses</p> Signup and view all the answers

    What term is used to describe the speed at which the shaft runs so that the additional deflection of the shaft from the axis of rotation becomes infinite?

    <p>Critical or whirling speed</p> Signup and view all the answers

    What factor contributes to the bending of a shaft carrying gears or pulleys?

    <p>Eccentricity and speed</p> Signup and view all the answers

    In a single rotor system, where is the node located?

    <p>At point N</p> Signup and view all the answers

    What is the force resisting the deflection 'y' in a rotating shaft with a rotor?

    <p>Stiffness of the shaft</p> Signup and view all the answers

    What causes a rotating shaft to deflect due to centrifugal force?

    <p>Centrifugal force acting through G</p> Signup and view all the answers

    What does the term 'critical or whirling speed' correspond to in terms of natural frequency?

    <p>Natural frequency divided by 2</p> Signup and view all the answers

    In a rotating shaft with a rotor, what happens when the circular frequency 'n' is equal to 'c'?

    <p>The value of y becomes infinite</p> Signup and view all the answers

    What determines the natural frequency for Rotor A in a two-rotor system?

    <p>Mass moment of inertia of rotor A</p> Signup and view all the answers

    What must be true for torsional vibrations to occur in a two-rotor system?

    <p>The two rotors must move in opposite directions and have the same frequency</p> Signup and view all the answers

    What affects the natural frequency in a three-rotor system?

    <p>Mass moment of inertia of rotor C</p> Signup and view all the answers

    What type of vibrations occur when the particles of the shaft or disc move in a circle about the axis of the shaft?

    <p>Torsional vibrations</p> Signup and view all the answers

    During transverse vibrations, what type of stresses are induced in the shaft?

    <p>Bending stresses</p> Signup and view all the answers

    In which type of vibration do the shaft particles move parallel to the axis of the shaft?

    <p>Longitudinal vibrations</p> Signup and view all the answers

    What occurs during transverse vibrations in terms of shaft behavior?

    <p>The shaft is straight and bent alternately</p> Signup and view all the answers

    What type of vibrations cause tensile and compressive stresses to be induced alternately in the shaft?

    <p>Transverse vibrations</p> Signup and view all the answers

    What is the term for vibrations where the shaft is twisted and untwisted alternately?

    <p>Circumferential vibrations</p> Signup and view all the answers

    What process does the refrigerant undergo in the condenser?

    <p>Condensing process</p> Signup and view all the answers

    What happens to the refrigerant as it passes through the expansion valve?

    <p>It expands</p> Signup and view all the answers

    During which process does the liquid refrigerant evaporate?

    <p>Expansion process</p> Signup and view all the answers

    What is the pressure at point 4 in the system?

    <p>$p_1$</p> Signup and view all the answers

    What does the refrigerant give to the surrounding condensing medium in the condenser?

    <p>Latent heat</p> Signup and view all the answers

    What is the speed at which the additional deflection of the shaft becomes infinite known as?

    <p>Critical or whirling speed</p> Signup and view all the answers

    In a rotating shaft with gear or pulleys, what force causes the shaft to bend?

    <p>Centrifugal force</p> Signup and view all the answers

    What happens to the value of deflection 'y' when the circular frequency 'n' equals 'c'?

    <p>It becomes infinite</p> Signup and view all the answers

    What is the unit for critical or whirling speed?

    <p>Revolutions per second</p> Signup and view all the answers

    In a two-rotor system, when do torsional vibrations occur?

    <p>When both rotors move in opposite directions</p> Signup and view all the answers

    What factor determines the bending of a shaft carrying gears or pulleys?

    <p>Speed of rotation</p> Signup and view all the answers

    Where does the node lie in a two-rotor system during torsional vibrations?

    <p>At the fixed end of the shaft</p> Signup and view all the answers

    'Free Torsional Vibrations' occur in a system where:

    <p>The rotor is fixed at one end of the shaft</p> Signup and view all the answers

    'Modulus of rigidity' represents the resistance of a shaft to:

    <p>Torsional vibrations</p> Signup and view all the answers

    'Efficiencies of both living and non-living beings depend to a great extent on the physical environment.' implies that:

    <p>'Efficiency' varies based on environmental factors</p> Signup and view all the answers

    What is the machinery known as that performs the operation of increasing the temperature inside a car?

    <p>Heat pump</p> Signup and view all the answers

    In a refrigeration system, what is the direction of heat flow?

    <p>From a lower temperature space to a higher temperature environment</p> Signup and view all the answers

    What does air conditioning involve controlling in addition to temperature?

    <p>Temperature, humidity, cleanliness, and air motion</p> Signup and view all the answers

    Why is controlling temperature alone not sufficient for comfort according to the text?

    <p>Humidity plays a crucial role in comfort</p> Signup and view all the answers

    Which city is used as an example in the text to explain the importance of controlling both temperature and humidity for comfort?

    <p>Shillong</p> Signup and view all the answers

    What additional parameter besides temperature and humidity is mentioned as essential for comfort in the text?

    <p>Air motion</p> Signup and view all the answers

    What must be done to pump heat into or out of a space according to the text?

    <p>Perform external work using a mechanical device</p> Signup and view all the answers

    What role does a heat pump play in controlling the temperature of a space?

    <p>Pumping heat in or out as needed</p> Signup and view all the answers

    'Heat flows from a body at a higher temperature to a body at a lower temperature' is an example of what concept?

    <p>'Water flows from a higher level to a lower level' principle</p> Signup and view all the answers

    'Heat is pumped out from a lower temperature space to a higher temperature environment' is characteristic of which system?

    <p>'Refrigeration system' operation</p> Signup and view all the answers

    What was the most significant development in refrigeration systems in the 1930s?

    <p>Invention of chlorofluorocarbon refrigerants</p> Signup and view all the answers

    What is the purpose of an evaporator in a refrigeration system?

    <p>To evaporate liquid ammonia</p> Signup and view all the answers

    When was the first two-stage modern compressor developed?

    <p>1915</p> Signup and view all the answers

    What is the primary function of an absorber in a vapor-absorption refrigeration system?

    <p>To absorb weak aqua ammonia</p> Signup and view all the answers

    Which development occurred when the refrigeration industry had stagnated on NH3 and SO2 as refrigerants?

    <p>Invention of chlorofluorocarbon refrigerants</p> Signup and view all the answers

    What is the purpose of a generator in a vapor-absorption refrigeration system?

    <p>To separate ammonia vapor</p> Signup and view all the answers

    What is the role of a condenser in a refrigeration system?

    <p>To condense ammonia vapor</p> Signup and view all the answers

    When did significant diversification in refrigeration systems begin to occur?

    <p>'Round 1920</p> Signup and view all the answers

    What is the primary purpose of air conditioning in buildings?

    <p>Providing comfortable conditions for people year-round</p> Signup and view all the answers

    What are the ventilation requirements for hospitals and medical buildings?

    <p>Use of 100 percent outdoor air and humidity limits</p> Signup and view all the answers

    In industrial air conditioning, what is the purpose of spot heating?

    <p>Warming a confined zone where a worker is located</p> Signup and view all the answers

    Why is control of humidity crucial in the printing industry?

    <p>To prevent static electricity issues</p> Signup and view all the answers

    What is the primary role of air conditioning in precision parts manufacturing?

    <p>Maintain uniform temperature, humidity, and filter air</p> Signup and view all the answers

    Why is air conditioning essential in computer rooms?

    <p>To control temperature, humidity, and cleanliness</p> Signup and view all the answers

    What major contributor to cooling load is found in vehicles that are air conditioned?

    <p>Heat from solar radiation</p> Signup and view all the answers

    Why is refrigeration important for food storage and distribution?

    <p>To extend the storage life of perishable foods</p> Signup and view all the answers

    What special temperature condition is required in the photographic-products industry?

    <p>-40°C for certain equipment testing</p> Signup and view all the answers

    What role does air conditioning play in extending the life of perishable foods in food storage?

    <p>Extending the storage life by maintaining low temperatures</p> Signup and view all the answers

    What is the main purpose of refrigeration and air conditioning?

    <p>To remove heat from spaces to provide comfort</p> Signup and view all the answers

    Why is it necessary to have control over the environment?

    <p>To enable living beings to perform better</p> Signup and view all the answers

    How does refrigeration work in preserving perishable food items?

    <p>By slowing down molecular motion and bacteria growth</p> Signup and view all the answers

    In refrigeration, where is the unwanted heat removed from a space transferred to?

    <p>Transferred to the surrounding environment</p> Signup and view all the answers

    How does refrigeration contribute to air conditioning in cars?

    <p>By transferring heat from inside the car to the surroundings</p> Signup and view all the answers

    What happens to the temperature inside a refrigerator when unwanted heat is removed?

    <p>The temperature decreases</p> Signup and view all the answers

    Why is it important for a car's interior to have a lower temperature than outside during summers?

    <p>To provide comfort during a hot drive</p> Signup and view all the answers

    What is the volume relationship between a car's interior and its surrounding environment during air conditioning?

    <p>The volume of the car is much less than its surroundings</p> Signup and view all the answers

    Why is refrigeration essential for preserving perishable food items?

    <p>To slow down bacterial growth and molecular motion.</p> Signup and view all the answers

    Why would it be uncomfortable to drive in a car without air conditioning during an Indian summer in Delhi or Kanpur?

    <p>Due to high external temperatures.</p> Signup and view all the answers

    What is the standard unit of refrigeration?

    <p>Ton refrigeration</p> Signup and view all the answers

    Which substance is commonly used as a refrigerant in a vapour compression cycle?

    <p>Ammonia (NH3)</p> Signup and view all the answers

    What role does the compressor play in a simple vapour compression refrigeration system?

    <p>Compressing the vapour refrigerant</p> Signup and view all the answers

    Where is the condensed liquid refrigerant stored in the system?

    <p>Receiver</p> Signup and view all the answers

    What is the function of the expansion valve in a vapour compression system?

    <p>Reducing the pressure and temperature of the refrigerant</p> Signup and view all the answers

    During which process of the theoretical vapour compression cycle does isentropic compression occur?

    <p>Compression Process</p> Signup and view all the answers

    What happens to the pressure and temperature of the vapour refrigerant during isentropic compression?

    <p>Pressure increases, temperature increases</p> Signup and view all the answers

    Which component of a vapour compression system cools and condenses the high-pressure vapour refrigerant?

    <p>Condenser</p> Signup and view all the answers

    What absorbs latent heat from the solution in a simple vapour compression system?

    <p>Evaporator</p> Signup and view all the answers

    Where is the liquid-vapour refrigerant evaporated and changed into vapour refrigerant at low pressure and temperature in a simple vapour compression system?

    <p>Evaporator</p> Signup and view all the answers

    What distinguishes the summer air conditioning system from the winter air conditioning system?

    <p>Summer air conditioning cools the space and removes extra moisture, while winter air conditioning heats the space and adds moisture.</p> Signup and view all the answers

    How is industrial air conditioning different from comfort air conditioning?

    <p>Industrial air conditioning includes air conditioning of printing plants and computer rooms, while comfort air conditioning deals with spaces like homes and offices.</p> Signup and view all the answers

    What was one method used to produce ice around 4000 years ago?

    <p>Keeping water in porous pots outside during the night</p> Signup and view all the answers

    Who obtained the first British Patent related to refrigeration in 1790?

    <p>Thomas Hariss and John Long</p> Signup and view all the answers

    Which pioneer developed a hand-operated refrigeration system using ether as the working fluid?

    <p>Jacob Perkins</p> Signup and view all the answers

    What was the purpose of Dr. John Gorrie's cold air machine patented in 1851?

    <p>To cure people suffering from high fever</p> Signup and view all the answers

    Instead of air or ether, what substance did Dr. James Harrison use in his refrigeration machine for brewery?

    <p>Sulfuric ether</p> Signup and view all the answers

    In which century were East Indians producing ice by dissolving salt in water to cool beverages?

    <p>4th century A.D.</p> Signup and view all the answers

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